Microwave reflector



March 10, 1970 w. F. REX 3, 4

MICROWAVE REFLECTOR.

Filed April 5, 1968 5 Sheets-Sheet 1 g 2, BY Will/am F Rex www- 22.

A 7' TORNE Y March 10, 1970 w. F. REX 3,500,430

MICROWAVE REFLECTOR Filed April 5. 1968 r 3 Sheets-Sheet z 48 l 32b 44 309A Fi 4 30d INVENTOR. William 5 Rex March 10, 1970 w. F. m 3,500,430

MICROWAVE REFLECTOR Filed April 5, 1968 r '3 Sheets-Sheet 3 JNVENTOR. 'Vfi'Iliam E Rex A TTORNEY United States Patent 3,500,430 MICROWAVE REFLECTOR William F. Rex, 6915 Lakewood Place, Lakewood, Colo. 80215 Filed Apr. 3, 1968, Ser. No. 718,507 Int. Cl. H01q 15/20 US. Cl. 343915 1 Claim ABSTRACT OF THE DISCLOSURE work is secured to a ground supported frame with a means for adjusting the reflecting surface in relation to the ground supported frame but providing a strong, rigid connection therebetween.

The use of microwave communication systems has greatly expanded in recent years, requiring more sophisticated and accurate equipment for the eflicient transmission of the microwaves. This type of system is a line-of-sight transmission of the radio waves, and one very effective method of transmitting the line-of-sight waves over or around obstacles is by the use of reflecting surfaces, called passive repeaters, which actually reflect the microwaves at an angle to be incident wave. Improvements in microwave transmitters and in transmitting antennae has substatially improved the character and the qualities of the microwave transmissions, particularly as to the shape and lateral extent of the transmitted waves.

According to the present invention I have provided an unobstructed, essentially flat reflecting surface which accurately reflects microwaves at an angle to the incident wave, without distortion of the wave. The reflecting surface is formed by interlocking extrusions each of which has a flat surface with smooth lineal edges for abutting a similar adjoining edge on the adjacent extrusions. This forms a smooth planar surface without interruptions across its extent, and the extrusions are made so that there is minimum clearance between adjacent extrusions thereby forming an essentially continuous planar surface for use in reflecting microwaves. This unit made of the joined extrusions is then secured to a rigid framework providing strength for the reflecting surface and maintaining its planar configuration under the influence of high winds and the like. The rigid framework is the attached to a ground supported frame which holds the reflecting surface in predetermined position. A lost motion connection is provided between the rigid framework and the ground supported frame to accurately hold the reflecting surface in its predetermined position, but permitting the members movement due to differential thermal expansion. Furthermore, the rigid framework is secured to the ground supported frame in such a manner to permit minor adjustment of the reflecting surface for accurate directional reflection of the incident beam.

Included among the objects and advantages of the present invention is a passive repeater which is provided with a planar, essentially unobstructed reflecting surface for microwave beams.

A further object of the invention is to provide a means for securing a large metal reflecting surface on a rigid backing in such manner as to allow differential thermal expansion of the surface and backing while maintaining the predetermined position of the reflecting surface.

A still further object of the invention is to provide a means for securing a reflecting surface on a ground supported frame with adjustment means which permits directional adjustment of the reflecting surface while maintaining the reflecting surface in the rigid predetermined position.

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustrations in which:

FIG. 1 is a perspective view of a passive repeater according tothe invention;

FIG. 2 is a side elevation view of the passive repeater of FIG. 1 mounted on its ground supported frame;

FIG. 3 is a detailed view of the reflecting surface and its mounting on a rigid frame;

FIG. 4 is an enlarged detail view of a lost motion connection for mounting joined extrusions on a rigid frame;

FIG. 5 is a side elevational view of a detail of a bottom and top connection between the rigid framework and the ground supported frame;

FIG. 6 is a side elevational view of an adjusting connector between the rigid framework and the ground supported frame; and

FIG. 7 is an enlarged view of the adjusting arrangement of FIG. 6 for changing the position of the reflecting surface in relation to the ground support frame.

As shown in FIG. 1 of the drawings, a passive repeater includes a reflecting structure, shown in general by numeral 10, which provides a flat surface 12 for reflecting microwaves and a framework, shown in general by numeral 14, which supports the flat surface 12. The unit 10 is supported on vertical columns or towers 16, 18 and 2.0 and is braced by diagonal framework members or A-frames 22, 24 and 26. As is well known, such a unit is mounted in a high place with the surface generally directed toward an antennae of a transmitter some distance away but at an angle to the incident beam from the transmitter so as to reflect the beam at a different angle thereto.

The unit 10, FIG. 3, consists of a series of interlocking extrusions 30a, 30b, etc. for example, aluminum extrusions, and these include interlocking flanges 32a along one side and 34a along the other side of the extrusion. The flanges 34 interlock with the flanges 32 of the adjacent extrusions. The reflective side is a smooth, planar surface. Such extrusions are known in the art, and included among many of the different types of extrusions which are usable for a reflecting surface are such as shown in US. Patent No. 3,100,556, issued Aug. 13, 1963 to E. J. Riter and US. Patent No. 3,111,203, issued Nov. 19, 1963 to the same inventor. The extrusions are preferrably designed to provide the interlocking flanges with a sharp corner at the reflecting surface which closely abutts a similar sharp corner on the next adjacent extrusion to thereby provide a tight, smooth joint with an effective continuous flat surface between two interlocked extrusions.

The assembled extrusions are secured to a rigid framework backing member, illustrated as general numeral 14 in FIG. 1, arranged to hold the interlocked extrusion with their reflective surface planar. This framework includes a series of perpendicular and vertical members to which the joined extrusions are secured. The framework includes vertical angle members 36 (to which the extru sions are secured), lower members 37 and upper members 38. The number of vertical members 36 is determined by the width and the length of the extrusions to be used as a passive repeater. For rigidity the angle members, to which the joined extrusions are attached, are provided with biased bridging members which includes 3 angles 39a, 39b, 390, etc., which are secured to the base angle members as by welding, bolting or the like and these extend outwardly in a general horizontal extension. Vertical backing angle members 40, which may follow the general pattern of the base angle members on the extrusions or may be of a different configuration, are rigidly secured to the outer ends of the horizontal members. The lateral braces 42a, 42b, etc., then are secured between the outer members and the inner members to provide the rigid framework for holding the joined extrusions. The extrusions include a body portion of considerable thickness along with their supporting flanges and strengthening ribs so that there is a substantial difference of thermal expansion and contraction between the interlocked extrusions and the rigid bridging frame member to which it is attached. The joined extrusions are, therefore, secured by lost motion connections, through the connecting flanges of the extrusions, to the angles of the base members of the framework to permit expansion of the extrusions along their width and breadth while maintaining the planar surface. As shown in detail in FIG. 4, a flange 32 on one side of an extrusion is interlocked with a flange 34 on a next adjacent extrusion, such as shown in the patents above mentioned, and a bolt 44 extending through an opening in these flanges secure the same to a web 36a of one of the angles or the rigid framework thereby supporting the joined extrusions. To provide for the lost motion, a hole 45 drilled through the joined flanges is larger than the diameter of nonthreaded portion 44a of the bolt, and in a similar manner a bolt hole 47 in the web 36a is larger than the diameter of the bolt at the non-threaded portion 44a. The bolt is provided with a head 48 and a locking type nut 49 to secure the parts together. The locking nut may be a fiber insert-type such as aircraft locking nuts. To maintain spacing of the metal parts, a series of washers are provided between theparts, and these include washers 50, 51 and 52 spacing respectfully the bolt head from the extrusion flanges, these flanges from the angle web, and the nut from the -web. Preferably, these washers are nylon or equilivent material which are essentially selflubricating and provide for relatively easy movement between the parts. The lock nut 39 is arranged to maintain the parts in the general configuration without loosenin Since the passive repeaters are usually in exposed positions they must be able to withstand substantial winds. With a 8 foot x foot passive repeater, for example, 24 bolts (described above) placed at various positions throughout the extrusions adequately secure the extrusions to the rigid framework. For this, quarter inch diameter steel bolts are satisfactory for securing the panels to the framework. For larger reflecting panels, for example, a forty foot by sixty foot panel, the number of bolts must obviously be increased to adequately secure the panel to the rigid framework backing.

The panel secured to-the rigid backing is then mounted on upright supports, in position for reflecting microwaves. As shown in FIG. 2, the supports include three upright columns, which may be of a configuration desired by the designer. As shown, triangular shaped columns are secured to concrete piers set in the ground in accordance with conventional practice. A series of diagonal braces are secured to the upright members of the columns providing the lateral stability of the columns. The columns include main vertical elements 55a, 55b and 550 with a plurality of diagonal bracing 56 in accordance with general practice providing a very rigid, light weight column. The biased bracing or A-frame members include a-main cord member 57 and a diagonal brace 58 provided with a series of interconnecting lateral braces 59 formed in general truss design configuration. The A-frame braces maybe joined together by means of horizontal bracings 60, shown in FIG. 1, for additional strength.

The rigid backing for the extrusions is secured to the framework by adjustable connection means which permits adjustment after attachment, for example, some 4 or so after installation of the reflecting surface on the columns. The bottom of the rigid backing for the extrusion is secured to the upright columns by means of an angle member 62 bolted, by a bolt 63, to the framework 14 and the opposite end is secured to the upright 55a of the column through an angle 64 which is bolted by bolt 65 to the main column 55a. A bolt 66 through the other web of the angle 66 is secured to the angle 62. When the hole for bolt 66 in angle 62 is drilled on location, this permits some distance adjustment between the frame 14 and the angle of 55a of the column. The top of the reflector and its framework backing is similarly secured to the columns as indicated in FIG. 2 at 62a. The bottom and the top of the rigid framing is preferably attached to each of the columns for support.

The panel and framework construction is secured to the columns above the bottom by means of a connection indicated in general by numeral 68 is FIG. 2, and shown in detail in FIGS. 6 and 7. An additional connection 68a is provided adjacent the top of unit which is essentially the same type of connection as the connector 68. In the connector shown in FIGS. 6 and 7, a brace member 70 is secured to the upright 40 of the rigid framework and is braced by means of diagonal braces 71 and 72. This brace provides a support for a stub or elongated bolt 73 secured by nuts 74 and 75 to the angle 40. The other end of this bolt is secured to laterals 77 and 78 secured between the upright angles 55a and 55c of the column. Nuts 79 and 80 provide an adjustment means for changing the distance between the two frames. Bracing members 81 and 82 may be provided for additional strength of the joint. A three-quarter inch rod 84 with a turn buckle, now shown, provides an additional connection between the two members for stability.

After the survey of the site has been completed the concrete piers are formed in position. The upright columns and A-frame bracing are attached to the cured piers for supporting the passive repeater. The extrusions are snapped together, secured to the rigid backing framework 14,and the unit is hoisted into place on the columns. The adjustable connectors are secured to both members, and the final position adjustments made for positioning the reflecting surface at its correct spacial angles. The bottom and top connections are then made to complete the structure.

While the invention has been illustrated by reference to particular embodiments, there is no intent to limit the spirit or scope of the invention so set forth except as defined in the following claim.

I claim:

1. A passive repeater comprising:

(a) a series of extruded form panels each including a base member having flange elements along opposite edges thereof, a flange element of one extruded panel overlapped and interlocked with a flange element of a contiguous panel thereby forming a rigid planar surface having an unobstructed reflecting surface, said interlocked flange elements being on the side opposite said reflecting surface;

(b) an open, rectangular backing framework, said framework including a plurality of spaced parallel frame elements having webs disposed in co-planar relation, the overlapping flange elements of said extruded from panels being positioned against corresponding edges of said webs;

(c) means connecting said flange elements to said frame elements, said connecting means including:

(1) registered apertures in said flanges and webs,

(2) bolts with nuts thereon extending through said registered apertures,

(3) said apertures being substantially larger than the diameter of said bolts, and

(4) a plurality of spaced self-lubricating washers 5 disposed on each bolt, said washers being disposed on opposite sides of said web and between the bolt head and said interlocked flanges thus permitting diflerential thermal movement between said elements upon thermal expansion and contraction thereof; (d) support means secured to the ground and extending thereabove; and (e) means securing said framework to said support means.

References Cited UNITED STATES PATENTS 6 1/ 1961 Kreitzberg. 5/ 1962 Peirce 24815 6/1962 Davis 343-915 10/1964 Ashton 343915 7/1964 Ashton 343915 4/1966 Rohn 343915 FOREIGN PATENTS 5/ 1960* France.

1911 Great Britain.

HENRY C. SUTHERLAND, Primary Examiner US. Cl. X.R. 

